Love and Depression, where do I go now?

I have been married for fifteen years and together twenty two. My husband had always been a bit of a loner, but so am I so that was not a problem until dperession hit with a baseball bat some five years ago. Where we used to love spending time with eachother bushwalking, watching movies, doing projects together on our farm, now there is three in this marriage, him, his depression and me. A lot of feelings now go unsaid, either because he doesn't want to share his feelings or I'm too scared to say anything that might push him over the edge. He is on medication but won't speak to any health professional and he says there is nothing to say. I am feeling more and more isolated and my friends and family tell me the only way to survive is to make a life for myself, my own friends, my own social life etc but that's not why I got married! We finally got some things said out in the open last night after he came home from work after having a particulariliy bad day where he lost his temper at a work colleague and felt ashamed and embarrased about it. He is a highly intelligent person who rarely seeks the advice of anyone and anything I suggest is nearly always dismissed. I am a health professional and am in regular contact with people in crisis and can see ways to help them but I am at a loss as to how to deal with my own, ever increasing isolation, any advice?